JP3683760B2 - Scroll compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a scroll compressor, and more particularly, to a scroll compressor provided with a fixed and movable scroll formed by projecting a spiral body on an end plate.
[0002]
[Prior art]
Conventionally, this type of scroll compressor is known as described in, for example, JP-A-58-128485. As shown in FIG. 9, the scroll compressor described in this publication is provided with a fixed scroll B formed by projecting a spiral body B2 on an end plate B1 on the inner upper portion of a sealed casing A, and this fixed scroll B A movable scroll C formed by projecting a spiral body C2 on the end plate C1 is supported in a vertically opposed manner so that the spiral bodies B2 and C2 mesh with each other, and on the lower side of the casing A. A motor D is provided, and a drive shaft E extending from the motor D is supported by a bearing housing F provided on the lower side of the movable scroll C, while a bearing upper end side of the drive shaft E is interlocked and connected to the movable scroll C. As the drive shaft F is driven, the movable scroll C is driven to revolve with respect to the fixed scroll B via a rotation prevention mechanism such as an Oldham ring.
[0003]
An intermediate pressure chamber G is provided between the movable scroll C and the bearing housing F on the lower back side, and the intermediate pressure chamber G1 communicates with the end plate C1 of the movable scroll C. A hole H is formed, and a part of the compressed gas fluid in the compression chamber is introduced from the intermediate pressure hole H to the intermediate pressure chamber G side. And the movable scroll C is pressed against the fixed scroll B with the intermediate pressure, whereby the scroll bodies B2 and C2 of the scrolls B and C are respectively attached to the end plates C1 and B1. The movable scroll C is prevented from separating downward with respect to the fixed scroll B during operation, and this separation causes the compression chamber side between the spiral bodies B2 and C2 to be separated from each other. Eliminating the occurrence of gas leakage to the low pressure side, thereby reducing the compression loss in the compression chamber.
[0004]
Further, in the above scroll compressor, in order to prevent over compression in the compression chamber, a plurality of relief ports I are formed in the fixed scroll B, and each relief port of the fixed scroll B is formed. Relief valves J that are opened when the internal pressure of the compression chamber becomes equal to or higher than a predetermined pressure are respectively provided at positions opposite to I. Thus, when the internal pressure of the compression chamber becomes equal to or higher than a predetermined pressure, the relief valve J is opened, a part of the compressed gas in the compression chamber is opened from the relief port I into the casing, and the This prevents over-compression in the compression chamber.
[0005]
[Problems to be solved by the invention]
However, in the above configuration, over-compression in the compression chamber can be prevented by the relief port I, but the intermediate pressure chamber G is formed between the spiral bodies B2 and C2 via the intermediate pressure hole H. Since the intermediate pressure chamber G is held at an intermediate pressure by communicating with the compression chamber, the gas fluid enters and exits between the intermediate pressure chamber G and the compression chamber. That is, when the intermediate pressure hole H is opened to the high-pressure compression chamber side, a high-pressure gas fluid flows from the compression chamber into the intermediate pressure chamber G, and the intermediate pressure hole H is connected to the intermediate pressure chamber G. When opening to the lower pressure compression chamber side, an intermediate pressure gas fluid flows into the compression chamber side from the intermediate pressure chamber G, so there is a problem in that compression loss and power loss are caused by the entry and exit of this gas fluid. . That is, FIG. 10 is a graph in which the vertical axis represents pressure and the horizontal axis represents compression volume. On the suction side, gas fluid is sucked into the compression chamber between the spiral bodies B2 and C2, and the movable scroll C The gas fluid is compressed in the compression chamber in accordance with the revolving motion of the gas, and shows the process of the gas fluid from the discharge port to the inside of the casing after the compression is completed, and the gas fluid is sucked into the compression chamber and sealed When an intermediate pressure gas fluid is introduced from the intermediate pressure chamber G into the compression chamber, the internal pressure of the compression chamber increases as shown by the alternate long and short dashed line in FIG. In addition, since the high pressure compression chamber is discharged to the intermediate pressure chamber G, a compression loss is generated accordingly.
[0006]
Further, since the fixed scroll and the movable scroll are in a high-pressure atmosphere, the suction gas in the suction pipe is heated by these scrolls. For this reason, there also exists a problem that the volumetric efficiency of the compression chamber by suction heating deteriorates.
[0007]
An object of the present invention is to provide a scroll compressor that can reduce over-compression while reducing compression loss and power loss in a compression chamber.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the invention described in claim 1 is provided with a fixed scroll 2 and a movable scroll 3 in which spiral bodies 22 and 32 project from end plates 21 and 31, and the spiral bodies 22 and 32 of both scrolls are provided. In the scroll compressor in which the compression chambers X and Y are formed by being opposed to each other, the inside of the hermetic casing 1 is partitioned by the bearing housing 5 and the fixed scroll 2 and the movable scroll 3 are formed in one partitioned space 1E. the compression element is disposed, guide the fluid discharged from the discharge port 23 of the compression element into the other space 1B, will place the motor 4 for driving the compression element in the space 1B of the other, of the fixed scroll 2 The spiral body 22 extends from the end of the winding to the vicinity of the end of the spiral of the scroll 32 of the movable scroll 3, and the inner surface of the extension is the vortex of the fixed scroll 2. And forms a curved continuous with the body 22, Oite to the fixed scroll 2, each of the fluid of the two compression chambers X1, the Y1 immediately before opening into the discharge port 23, the compression chambers X, the Y When the ratio of the volume of each compression chamber X1, Y1 to the volume of each compression chamber X, Y when the fluid is closed becomes the same value, the position is sequentially relieved to the other space 1B with a phase difference. A relief valve is provided.
[0009]
In addition to the invention according to claim 1, the invention according to claim 2 is configured such that the suction pipe 7 passes through the sealed casing 1 and opens into the low-pressure chamber 1E, and the fixed scroll 2 and the movable scroll. 3 is extended in the vicinity of the winding end.
[0010]
In the first aspect of the present invention, a suction pressure space is formed around the compression element composed of the fixed and movable scrolls 2 and 3, and a discharge pressure space is formed around the motor 4. Therefore, since the gas sucked into the compressor does not come into contact with the high-temperature discharged gas or the motor, it is possible to realize a configuration with high volume efficiency with little suction heating.
[0011]
In the second aspect of the present invention, the gas sucked into the compressor is difficult to directly contact the heat transmitted through the casing 1 and the slightly hot gas in the suction pressure space. It becomes composition.
[0012]
【Example】
FIG. 1 shows a vertical scroll compressor, and a fixed scroll 2 in which a spiral body 22 projects from an end plate 21 on the inner upper part of a hermetic casing 1 and a discharge port 23 is formed at the center of the end plate 21; The movable scroll 3 formed by projecting a spiral body 32 on the end plate 31 is supported in a vertically opposed manner so that the spiral bodies 22 and 32 are engaged with each other, and a motor 4 is provided on the lower side of the casing 1. The drive shaft 41 extending from the motor 4 is supported by a bearing housing 5 fixed to the lower side of the movable scroll 3, while the upper end side of the bearing of the drive shaft 41 projects into the center of the back surface of the end plate 31 of the movable scroll 3. The movable scroll 3 is inserted into a boss 33 provided, and the movable scroll 3 is made public with respect to the fixed scroll 2 through an anti-rotation mechanism comprising an Oldham ring 50 as the drive shaft 41 is driven. And so as to driven.
[0013]
Further, a cover body 24 covering the upper side of the discharge port 23 is attached to the fixed scroll 2 via a fixing bolt or the like, and the cover body 24 is fixed to a support plate 6 fixed to the inner upper side of the casing 1. The support plate 6 is provided with a communication hole 61 communicating with the discharge port 23. Further, the fixed scroll 2 is connected with a suction pipe 7 that penetrates the casing 1 and enters the casing 1, and the discharge chamber 1A of the casing 1 in which the communication hole 61 is opened, The motor 4 and the space 1B of the bearing housing 5 are communicated with each other through a communication path 1C to form a high-pressure dome structure in which the inside of the casing 1 has a high pressure, and a discharge pipe 8 is opened in the space 1B.
[0014]
Then, by rotating the drive shaft 41 accompanying the driving of the motor 4, the movable scroll 3 is driven to revolve with respect to the fixed scroll 2, whereby the spiral bodies 22 of the scrolls 2, 3 from the suction pipe 7. A gas fluid is sucked from a suction portion formed between 32 and compressed in a compression chamber between the spiral bodies 22 and 32, and the compressed gas fluid is passed from the discharge port 23 through the communication hole 61 and the communication path 1C. Then, the ink is discharged into the space 1B and discharged from the space 1B to the outside through the discharge pipe 8.
[0015]
In the above configuration, a back chamber 9 is formed around the boss portion 33 between the bearing housing 5 and the movable scroll 3, and the back chamber 9 is subjected to the high pressure in the casing 1. ing. That is, the back chamber 9 is supplied with high-pressure lubricating oil that is pumped from the bottom oil reservoir of the casing 1 through the inside of the drive shaft 41 to each lubrication location, and the high-pressure pressure acts. The movable scroll 3 is pressed toward the fixed scroll 2 by the high pressure acting on the back chamber 9. As shown in FIGS. 2 and 3, the discharge port is provided in the compression chambers X and Y formed between the spiral bodies 22 and 32 of the scrolls 2 and 3 in the end plate 21 of the fixed scroll 2. A relief valve 10 is provided for communicating the compression chambers X1 and Y1 immediately before opening to the discharge chamber 1A, and a relief valve that allows the relief port 10 to flow only from the compression chambers X1 and Y1 to the discharge chamber 1A. 11 is provided, and a valve presser 12 is provided on the upper side of the relief valve 11.
[0016]
More specifically, on the end plate 21 of the fixed scroll 2, two relief ports 10, 10 that connect the two compression chambers X 1, Y 1 immediately before being opened to the discharge port 23 to the discharge chamber 1 A are formed. The relief valves 11 and 11 are provided in the relief ports 10 and 10, respectively, and the valve pressers 12 and 12 are attached to the upper sides of the relief valves 11 and 11, respectively. As shown in FIG. 3, the relief valves 11 and 11 and the valve retainers 12 and 12 include a pair of relief valves 11 and 11 as a connecting piece 11a and a pair of valve retainers 12 and 12 as a connecting piece 12a. By integrating them, each relief valve 11 and each valve presser 12 are made into one part so that the number of parts can be reduced. Further, the relief valve 11 and the valve retainer 12 are fixed to the base plate 21 of the fixed scroll 2 on the end plate 21 of the fixed scroll 2 on the both sides of the connecting pieces 11a and 12a in the length direction. It is trying to tighten together.
[0017]
Next, the effect | action by the above structure is demonstrated. During operation by the scroll compressor, the suction gas fluid from the suction pipe 7 is introduced into the inside from a suction portion formed on the outer side of each spiral body 22, 32 in each scroll 2, 3, The compressed gas fluid is compressed in the compression chambers X and Y, and the compressed gas fluid is guided from the discharge port 23 through the communication hole 61 of the support plate 6 to the space 1B from the discharge chamber 1A. And discharged to the outside. At this time, the back chamber 9 is supplied with high-pressure lubricating oil pumped from the bottom oil reservoir of the casing 1 through the inside of the drive shaft 41 to each lubricating portion, and a high pressure acts. Thus, the movable scroll 3 is pressed against the fixed scroll 2 side. Accordingly, the movable scroll 3 is reliably prevented from separating from the fixed scroll 2, the spiral bodies 22, 32 can be brought into close contact with the end plates 31, 21, respectively, and the compression chambers X, Y It is possible to prevent the gas leakage from the low pressure side to the compression chambers X and Y and reduce the compression loss and power loss.
[0018]
In addition, the fixed scroll 2 communicates the first compression chambers X1, Y1 immediately before opening to the discharge port 23 of the compression chambers X, Y and the discharge chamber 1A through relief ports 10, 10. Since each relief port 10 is provided with relief valves 11 and 11 that allow only the flow from the compression chambers X1 and Y1 to the discharge chamber 1A, the pressure in the compression chambers X1 and Y1 is equal to or higher than the pressure in the discharge chamber 1A. At this time, each of the relief valves 11 is opened, and a part of the compressed gas in the compression chambers X1 and Y1 is opened from the relief ports 10 to the discharge chamber 1A, so that the inside of the compression chambers X1 and Y1. It is possible to prevent over-compression. Accordingly, it is possible to prevent the load and driving torque on the bearing of the bearing housing 5 from becoming abnormally high.
[0019]
That is, when used for refrigerant compression of the refrigeration apparatus, if the pressure ratio determined by the system of the refrigeration apparatus, that is, the pressure ratio determined by the condensation pressure and the evaporation pressure is lower than the design pressure ratio of the scrolls 2 and 3, in other words, evaporation. When the suction pressure determined by the pressure increases and the pressure ratio determined by the system becomes lower than the design pressure ratio, or conversely, the discharge pressure determined by the condensation pressure decreases and the pressure ratio determined by the system becomes lower than the design pressure ratio, the relief port 10 is set. When not provided, the high pressure P02 in the compression chambers X and Y increases as shown by the compression characteristic curve R2 in FIG. 5, whereas when the relief port 10 is provided, as shown by the compression characteristic curve R1 in FIG. The high pressure P01 in the compression chambers X and Y can be lowered compared to the high pressure P02. In FIG. 5, P1 is a low pressure when the compression chambers X and Y are closed.
[0020]
If the pressure ratio determined by the system is lower than the design pressure ratio, the separating force between the fixed scroll 2 and the movable scroll 3 increases, and the movable scroll 3 is fixed to the fixed scroll 2 as indicated by the dotted line Px in FIG. The pressing force, that is, the thrust bearing load decreases, the movable scroll 3 becomes unstable and gas leakage occurs, and conversely, the load and driving torque on the bearing of the bearing housing 5 increase, but the relief port 10 Even when the pressure ratio determined by the above-described system is low, that is, when it is over-compressed or when it is over-compressed by liquid compression, the pressing force that presses the movable scroll 3 against the fixed scroll 2, that is, thrust The bearing load can be increased, so that the movable scroll 3 is separated from the fixed scroll 2. It is possible to prevent the movable scroll 3 from becoming unstable and to prevent gas leakage, and yet to increase the load and driving torque on the bearing of the bearing housing 5. It can be prevented.
[0021]
Moreover, in order to prevent the occurrence of over-compression in the compression chambers X1, Y1, the compression chambers X1, Y1 and the back side of the movable scroll are communicated with each other via an intermediate pressure hole as in the prior art. The pressure is not applied to the movable scroll. In other words, the gas fluid is not allowed to enter and exit between the compression chambers X1 and Y1 and the intermediate pressure chamber, but the rear chamber 9 provided on the rear side of the movable scroll 3 Since the high pressure in the casing 1 is applied and the movable scroll 3 is pressed against the fixed scroll 2 side, the compressed gas fluid is moved from the high pressure side to the low pressure side through the intermediate pressure chamber as in the prior art. Compression loss and power loss due to leakage can be eliminated.
[0022]
In the embodiment described above, the end of winding of the spiral body 22 in the fixed scroll 2 and the end of winding of the spiral body 32 in the movable scroll 3 have a phase difference of 180 degrees, and each of the spiral bodies 22, 32. Is a general scroll compressor as a comparative example in which the suction ports of the two compression chambers X and Y formed by the above are provided at symmetrical positions. However, as shown in FIG. The scrolls 2, 3 may be formed asymmetrically by providing an involute curve-shaped extension 22 a extending from the end to the vicinity of the end of winding of the spiral body 32 in the movable scroll 3. In this case, the relief port 10 is opened at a position alternately communicating with the two compression chambers X and Y formed between the spiral bodies 22 and 32 of the scrolls 2 and 3, that is, at a position indicated by a solid line in FIG. As a result, only one relief port 10 is provided, and this relief port 10 is alternately communicated with the first compression chambers X1 and Y1 by the end plate 21 of the fixed scroll 2 when the movable scroll 3 is driven to revolve. Therefore, as shown by the solid line and the dotted line in FIG. 4, the workability can be improved as compared with the case where the relief port 10 is provided for each compression chamber X, Y. In addition, you may make it the extension part 22a of the said spiral body 22 form only the inner surface in involute curve shape.
[0023]
That is, as described above, when the scroll 22 of the fixed scroll 2 is provided with the involute-curved extension 22a and the scrolls 2 and 3 are asymmetrical, the spiral between the spirals 22 and 32 is the same. When the gas fluid is compressed in the first compression chambers X1 and Y1, the gas fluid is compressed with a predetermined phase difference between the compression chambers X1 and Y1, as shown in FIG. By providing only one relief port 10 at the position, when the revolution scroll 2 is driven to revolve, the relief port 10 is alternately opened to the first compression chambers X1 and Y1 for a predetermined period as shown in FIG. It is. At this time, one relief port 10 formed on the end plate 21 of the fixed scroll 2 is formed to have a hole diameter smaller than the thickness of the spiral body 22 provided on the end plate 21 and as close as possible to the thickness of the spiral body 22. In this way, it is possible to reduce the resistance when the gas fluid passes through the relief port 10, and from the high pressure side to the low pressure side of the compression chambers X and Y through the relief port 10. It is possible to prevent the gas fluid from leaking and causing a compression loss.
[0024]
Further, as shown in FIG. 8, a discharge valve 25 for opening and closing the discharge port 23 is attached to a portion facing the discharge port 23 provided on the end plate 21 of the fixed scroll 2 and the discharge valve 25 is attached. The relief valves 11, 11 may be integrally extended from the base 25a. In this case, since the discharge valve 25 and the relief valves 11 and 11 can be made into one part, the number of parts can be reduced, the cost can be reduced, and the assembling property can be improved. In addition, the valve presser which controls the lift of a valve is provided in the upper part of these valves similarly to FIG.
[0025]
【The invention's effect】
As described above, according to the invention described in claim 1, in the scroll compressor having the asymmetric spiral structure, the sealed casing 1 is partitioned by the bearing housing 5, and the compression element including the fixed scroll 2 and the movable scroll 3 is provided. Since the periphery is the suction pressure space and the periphery of the motor 4 is the discharge pressure space, it is possible to realize a configuration with low volumetric suction and high volume efficiency.
[0026]
According to the second aspect of the present invention, the gas sucked into the compressor becomes difficult to directly contact the heat transmitted through the casing 1 and the slightly hot gas in the suction pressure space. It becomes a high composition.
[Brief description of the drawings]
FIG. 1 is a partially omitted longitudinal sectional view showing the overall structure of a scroll compressor according to the present invention.
FIG. 2 is an enlarged cross-sectional view showing a part of a fixed scroll provided with a relief port and a relief valve.
FIG. 3 is a plan view of FIG. 2;
FIG. 4 is an explanatory diagram of fixed and movable scrolls that are asymmetrical.
FIG. 5 is a graph showing a compression curve with and without a relief port.
FIG. 6 is a graph showing the relationship between thrust bearing load and pressure ratio.
FIG. 7 is a graph showing a compression curve of an asymmetric scroll.
FIG. 8 is a plan view corresponding to FIG. 3 of an embodiment in which a discharge valve is provided at the discharge port.
FIG. 9 is a longitudinal sectional view showing a conventional scroll compressor.
FIG. 10 is a graph showing a conventional compression curve.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sealing casing, 1A High pressure chamber, 2 Fixed scroll, 3 Movable scroll, 21,31 End plate, 22,32 Spiral body, 23 Discharge port, 25 Leaf type discharge valve, 10 Relief port, 11 Relief valve, X, Y Compression chamber , X1, Y1 Compression chamber immediately before the discharge port is opened.

Claims (2)

A fixed scroll (2) and a movable scroll (3) each having a spiral body (22) (32) projecting from an end plate (21) (31) are provided, and the spiral body (22) of both scrolls (2) (3). In the scroll compressor in which the compression chambers (X, Y) are formed by facing and engaging (32),
The sealed casing (1) is partitioned by the bearing housing (5), and the compression element (2, 3) composed of the fixed scroll (2) and the movable scroll (3) is arranged in one partitioned space (1E). A motor that guides the fluid discharged from the discharge port (23) of the compression element (2, 3) to the other space (1B) and drives the compression element (2, 3) in the other space (1B). (4) is arranged,
The spiral body (22) of the fixed scroll (2) extends from the winding end to the vicinity of the winding end of the spiral (32) of the movable scroll (3), and the inner surface of the extension is the fixed scroll. (2) has a continuous curvilinear shape to the spiral body (22),
Oite to the fixed scroll (2), each of the fluid of said two compression chambers immediately before opening the discharge port (23) (X1, Y1) in the respective compression chambers (X, Y) wherein the fluid to When the ratio of the volume of each compression chamber (X1, Y1) to the volume of each compression chamber (X, Y) at the time of closing becomes the same value, the relief is sequentially relieved to the other space (1B) with a phase difference. A scroll compressor comprising a relief valve at a position . The suction pipe (7) passes through the closed casing (1) and opens into the one space (1E), and extends near the winding end of the fixed scroll (2) and the movable scroll (3). The scroll compressor according to claim 1 provided.

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